This invention relates to a coil spring mounting and assembly that extends and improves the functionality and useful life of the coil spring. As a spring coil is used it is flexed and bent, the present invention extends the useful life by decreasing the curvature and increasing the resistance to bending, while simultaneously providing positive bend control to the spring.
1. Field of the Invention
The present invention relates to a coil spring assembly that contains within it means for positively limiting the bending radius thereof Particularly, the present invention relates to a coil spring that can be used in exercise devices to provide resistance for resistive type exercise. Hence, the coil spring in such a device will be stressed, deformed, flexed and bent to acquire adequate resistive force to be effective in the exercise device. It is also contemplated within the present invention that such an improved coil spring assembly as described herein can be used in many other devices. For example, the present invention can be used in a chair that can be used as an office chair and having incorporated therein various resistive devices useful for exercise while seated in the chair.
Various coil spring devices have been put forward and described in the prior art to attempt to present exercise units that use the functionality and characteristics of a coil spring. Prior coil spring and bending devices may employ pulleys, ropes, multiple mechanisms, spring biased levers and the like to provide resistance to a particular motion.
Further, many of the prior art devices seek to accomplish automatic restoration to a rest position. Such devices, for example, use a spring to restore a connected lever arm back to the rest position. However, when the lever arm is moved to its maximum position in one direction, sudden release of the lever arm attached to the spring assembly could cause the lever arm to quickly return to its rest position. Anyone accidentally in the way of such a swiftly moving lever arm could be injured.
Therefore, incorporated in the present invention there is provided an improved coil spring assembly mounting with bend control. As in any exercise device, two-way active resistance is desirable in both the flexion and extension movements. These movements are effectively provided in the present invention.
2. Description of the Prior Art
Hitherto, various types of exercise devices have been proposed that would allow some form of aerobic arm exercise, most of the devices of the prior art rely on the extension of coil springs or elastomeric members for their resistance against which exercise can be performed. Among these devices there are those that have both dangerous pinch points and do not include means for preventing injury when a resistance member is accidentally broken or suddenly released when under tension.
The structure of conventional exercise benders using conventional coil springs is shown in FIGS. 1A and 1B. As the steel spring coil is manufactured minor flaws can easily occur in the operations of drawing and heat treatment. Further, as the steel coil is bent, normally most all of the bending takes place in the first loop adjacent to its rigid mounting point. Severe bending at this point is due to the fact that this is the point of maximum leverage. As a result, this extreme bending at this point causes internal stress and the crystal structure of the steel spring coil changes to a more crystalline form and can be easily subject to the effect of stress concentration and over hardness with use, as in bending and flexing. The steel spring coil will soon become fragile and easily break during use (as shown in FIG. 1) after only a short period of flexing and bending.
Further, the steel spring coil during fabrication and use is susceptible to external damage such as scratches or indentations which adversely affects its metal crystallization. Consequently, when internal stress is concentrated at the damaged spot so as to have the metal crystal involved at the spot, the steel spring coil will also be broken once the application of the external force is beyond its load limit.
U.S. Pat. No. 4,489,937 relates to a dyna-bender exercise device having safety features such as a center cord with a pair of cup-shaped positioning anchors installed for protection against damage and user injury. However, the coil spring therein is capable of extreme bending adding to the stress force that may damage the spring without controls to lessen the extent of the force and leverage.
U.S. Pat. No. 2,474,690 relates to a flexible connector which will not break in use, and the bending thereof is positively limited so that it can not buckle or stretch out of shape. The device of the Patent is a coil spring with support couplings at its opposite ends. Extending through the coil is a normally slack flexible tension member, such as a chain, connected to the couplings. The slack allows the coil to bend about 90 degrees before the slack in the chain is stretched taut to prevent further bending of the coil. The device of ""690 does not progressively decrease the leverage for a predetermined portion of the bend.
U.S. Pat. No. 1,485,036 discloses a universal joint in which a spring transmits torque between axially aligned cylindrical shafts. The ends of the shafts are tapered so that they will not contact the spring when the shafts are not in alignment.
Other devices utilize various forms of interactive movement to produce resistive forces to produce resistance. However, there is no mention of using a coil spring with a means for increasing the resistance to bending while the coil spring is undergoing bending.
The present invention relates to an improved fully functional coil spring assembly applicable to various attachments. It is accordingly a primary object of the present invention to provide a coil spring assembly for mounting that mitigates destructive crystallization in the coil spring, thus minimizing breakage of the coil spring. The mitigation of the crystallization is accomplished by decreasing the curvature when the coil spring is bent thus distributing the bending force over several coils. The coil spring assembly of the present invention has installed therein a tapered shaft for overcoming the defects of the prior art coil springs.
It is an object of the present invention to provide a coil spring assembly which is strong and durable which will not break in use and the bending of which is positively limited, so that the spring cannot buckle, stretch out of shape or break by repeated or continuous bending.
A further object of this invention is to establish positive bend control from either the inside or the outside of the coil spring.
It is a further object of the present invention to provide positive bend control to the coil spring in the form of a tapered shaft internally positioned in the spring coil. It is an object to provide a coil spring connector which is suitable for various attachments.
It is a further object of the present invention to provide a positive bend control to the coil spring in the form of an external curved surface which allows bending of the spring and control thereof in any direction from the mounting area. Likewise, there will be provided external positive bend control of a coil spring limited to one direction.
A further object of the present invention is to provide a resistive coil spring device that can be used in exercise equipment, such as an attachment to a chair wherein the seated person can perform certain exercises while seated therein.
The foregoing features, advantages, and benefits of the invention, along with additional ones, will be seen in the following description and claims which should be considered in conjunction with the accompanying drawings. The drawings disclose preferred embodiments of the present invention according to the best mode contemplated at the present time in carrying out this invention.